The present invention generally relates to trucks, and more particularly to improvements in transport trucks for coal mining operations. More specifically, this invention relates to a safety apparatus for transmitting the torque produced by a motor from within an explosion-proof container to a suitable driving mechanism located exterior to the container. The invention provides a motor and associated exterior drive mechanism for a mining car constructed in such a manner that any sparks emitted by the motor or explosions occurring within the motor housing box will be contained and extinguished within the motor housing box thereby eliminating a primary cause of potential mine explosions.
In the process of extracting coal or any ore from the interior of a mine, it is customary and necessary for mining vehicles to be used. The vehicles are used for the transportation of individual miners, mining tools, and often used for the actual physical extraction of the coal or ore itself.
The mining car generally consists of a vehicle frame, front and rear axle, four wheels which are either constructed to move upon rails similar to those used for railroads or upon a flat road bed, a motor, a power source for the motor usually consisting of a series of batteries, and a gearing mechanism for transmitting the power of the motor to the wheels of the car.
Recently, the United States Bureau of Mines and in particular MESA has set strict safety requirements for all machinery used within mines. Specifically, MESA requires that all mining machinery that is used at or near the working and digging area be "Permissible" i.e., every electrical component, including motors, headlights, electrical motor starter, control switches, and all wiring must be housed in well designed steel boxes with special covers and wire guards.
These requirements were deemed necessary to insure that any sparking or short circuiting occurring within the steel boxes remained inside these enclosures and did not escape to the mine air which tends to be highly explosive.
Due to these strict governmental safety requirements, mining cars and machinery which are presently constructed are extremely complicated and expensive.
The simple and sturdy construction of the invention eliminates most of the complicated and expensive components now used in mining cars while still maintaining a self-propelled machine that is explosion-proof in accordance with the aforementioned safety standards.
The primary aspect of the invention provides an inexpensive "open" type motor inside an electrical starter control box. The necessary driving transmission is located on the outside wall of this control enclosure with a "permissible" drive shaft connecting the two.
Another aspect of the invention is to provide a starter motor transmission control package which may be added to stationary mining machinery to drive pumps, conveyors, loading machines and equipment which does not require complicated switching controls or large motors with resulting heat dissipation problems.